Semiconductor Component and Illumination Device

ABSTRACT

A semiconductor component and an illumination device is disclosed. In an embodiment the semiconductor component includes a semiconductor chip configured to generate a primary radiation having a first peak wavelength and a radiation conversion element arranged on the semiconductor chip. The radiation conversion element includes a quantum structure that converts the primary radiation at least partly into secondary radiation having a second peak wavelength and a substrate that is transmissive to the primary radiation.

This patent application is a national phase filing under section 371 ofPCT/EP2015/061388, filed May 22, 2015, which claims the priority ofGerman patent application 10 2014 107 472.6, filed May 27, 2014, each ofwhich is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present application relates to a semiconductor component and to anillumination device.

BACKGROUND

For the backlighting of a display device, for example liquid crystaldisplays (LCDs), light emitting diodes can be used as radiation sources.However, such applications require a high gamut in order to be able torepresent the greatest possible proportion of the colors perceptible tothe human eye. By way of example, by means of LEDs that emit in the bluespectral range and a phosphor that emits in the yellow spectral range,radiation that appears white to the human eye can be generated with highefficiency, but with a reduced gamut. By adding further phosphors, thegamut can be improved but the efficiency decreases. A high color gamutcan furthermore be achieved if three mutually different light emittingdiodes directly generate radiation in the red, blue and green spectralranges. However, this requires a complex electronic control on accountof the driving of three individual colors.

SUMMARY OF THE INVENTION

Embodiments provide mixed radiation with high efficiency.

In accordance with at least one embodiment of the semiconductorcomponent, the semiconductor component comprises a semiconductor chipprovided for generating a primary radiation having a first peakwavelength. The first peak wavelength is in the ultraviolet or bluespectral range, for example. By way of example, the semiconductor chipcomprises an active region provided for generating the first peakwavelength. The active region is for example part of a semiconductorbody comprising a semiconductor layer sequence deposited for exampleepitaxially on a growth substrate. By way of example, the semiconductorchip comprises a carrier, on which the semiconductor body comprising thesemiconductor layer sequence with the active region is arranged. Thecarrier mechanically stabilizes the semiconductor body. The carrier canbe the growth substrate for the semiconductor layer sequence.Alternatively, the carrier can be different than a growth substrate forthe semiconductor layer sequence.

The semiconductor chip expediently comprises a first connection area anda second connection area for electrically contacting the semiconductorchip. The first connection area and the second connection area can bearranged on the same side of the semiconductor chip or on opposite sidesof the semiconductor chip.

In accordance with at least one embodiment of the semiconductorcomponent, the semiconductor component comprises a radiation conversionelement, which converts the primary radiation at least partly intosecondary radiation having a second peak wavelength. The secondaryradiation has, in particular, a greater peak wavelength than the primaryradiation. By way of example, the second peak wavelength is in thegreen, yellow or red spectral range.

In particular, the radiation conversion element is provided for onlypartly converting the primary radiation of the semiconductor chip, suchthat the semiconductor component emits overall a mixed radiationcomprising the primary radiation and the secondary radiation. By way ofexample, the mixed radiation is light that appears white to the humaneye.

In accordance with at least one embodiment of the semiconductorcomponent, the radiation conversion element comprises a quantumstructure, which converts the primary radiation at least partly intosecondary radiation having the second peak wavelength.

In the context of the application, the designation quantum structureencompasses in particular any structure in which charge carriers mayexperience a quantization of their energy states as a result ofconfinement. In particular, the designation quantum structure does notinclude any indication about the dimensionality of the quantization. Ittherefore encompasses, inter alia, quantum wells, quantum wires andquantum dots and any combination of these structures.

By way of example, the quantum structure comprises a plurality ofquantum layers between which barrier layers are arranged. For example,the quantum layers and the barrier layers form a multi quantum well(MQW) structure. The radiation conversion element comprises for examplea substrate, which is transmissive to the primary radiation. Thesubstrate serves in particular for mechanically stabilizing the quantumstructure. By way of example, the substrate is at least five times asthick as the quantum structure. The substrate can be a growth substratefor the for example epitaxial deposition of the quantum structure.Alternatively, the substrate can also be different than the growthsubstrate for the quantum structure. The semiconductor component canalso comprise more than one such radiation conversion element. By way ofexample, two or more radiation conversion elements which emit radiationhaving the same peak wavelength can be arranged one above another. Theefficiency of the radiation conversion can thus be increased.

The substrate of the radiation conversion element covers thesemiconductor chip in particular over a large area, for example to theextent of at least 20% or to the extent of at least 50% in a plan viewof the semiconductor chip. The substrate can cover the semiconductorchip as much as completely.

In at least one embodiment of the semiconductor component, thesemiconductor component comprises a semiconductor chip provided forgenerating a primary radiation having a first peak wavelength, and aradiation conversion element arranged on the semiconductor chip. Theradiation conversion element comprises a quantum structure, whichconverts the primary radiation at least partly into secondary radiationhaving a second peak wavelength. Furthermore, the radiation conversionelement comprises a substrate, which is transmissive to the primaryradiation.

In accordance with at least one embodiment of the semiconductorcomponent, the radiation conversion element containsAl_(x)In_(y)Ga_(1-x-y)N, Al_(x)In_(y)Ga_(1-x-y)P orAl_(x)In_(y)Ga_(1-x-y)As. It holds true here in each case that 0≦x≦1,0≦y≦1 and x+y≦1. Radiation in the green, yellow or red spectral rangecan be generated efficiently with these materials. In principle,however, any semiconductor material whose band gap is suitable forgenerating secondary radiation having the second peak wavelength to begenerated is suitable for the radiation conversion element.

In accordance with at least one embodiment of the semiconductorcomponent, the first peak wavelength is less than the second peakwavelength. By way of example, the first peak wavelength is in the bluespectral range and the second peak wavelength is in the green, red oryellow spectral range. By way of example, the first peak wavelength isin the blue spectral range and the second peak wavelength is in thegreen spectral range. Radiation in the green spectral range is thereforenot generated by means of a semiconductor chip that emits in the greenspectral range, but rather by means of a radiation conversion.

In accordance with at least one embodiment of the semiconductorcomponent, the semiconductor component comprises an emitter for emittinga third peak wavelength. The term “emitter” generally denotes an elementthat emits radiation upon excitation. The excitation can be effectedelectrically or optically, for example.

The first peak wavelength, the second peak wavelength and, ifappropriate, the third peak wavelength are expediently mutuallydifferent in each case. By way of example, a difference between the peakwavelengths is at least 50 nm in each case.

By way of example, a respective one of the first, second and third peakwavelengths is in the blue spectral range, in the green spectral rangeand in the red spectral range. In the case of a first peak wavelength inthe blue spectral range and a second peak wavelength in the greenspectral range, the third peak wavelength is in the red spectral range,for example.

In accordance with at least one embodiment of the semiconductorcomponent, the semiconductor component comprises a reflector layer. Thereflector layer contains for example a polymer material filled withreflective particles. By way of example, the particles contain titaniumdioxide, zirconium oxide or aluminum oxide. The reflector layer has areflectivity of at least 80% for example for the peak wavelength of theprimary radiation.

By way of example, the reflector layer is molded onto the semiconductorchip and/or onto the radiation conversion element. By way of example,the reflector layer at least regionally adjoins the semiconductor chipand/or the radiation conversion element directly. The reflector layer isproducible for example by means of a molding method. A molding method isunderstood generally to mean a method by which a molding compound can beconfigured in accordance with a predefined shape and hardened asnecessary. In particular, the term molding method encompasses molding(casting), injection molding, transfer molding, compression molding andfoil assisted molding.

In accordance with at least one embodiment of the semiconductorcomponent, the reflector layer is arranged in a beam path between theemitter and the radiation conversion element. The reflector layer thusprevents a direct beam path between the emitter and the radiationconversion element. Absorption losses within the semiconductorcomponent, for example as a result of absorption of the radiation havingthe second peak wavelength in the emitter and/or radiation having thethird peak wavelength in the radiation conversion element, are thusavoided or at least reduced.

In accordance with at least one embodiment of the semiconductorcomponent, the emitter is a further radiation conversion element. By wayof example, the further radiation conversion element comprises aphosphor for generating the radiation having the third peak wavelength.Alternatively, the emitter can comprise a further quantum structure forgenerating the radiation having the third peak wavelength. The furtherquantum structure can be embodied in particular as described inassociation with the quantum structure, wherein the quantum structureand the further quantum structure expediently emit in mutually differentspectral ranges.

In accordance with at least one embodiment of the semiconductorcomponent, the radiation conversion element and the further radiationconversion element are arranged alongside one another on thesemiconductor chip. The radiation conversion elements are arranged inparticular in a manner free of overlap alongside one another on thesemiconductor chip. The radiation conversion element and the furtherradiation conversion element can adjoin one another or be spaced apartfrom one another. By way of example, the reflector layer is arrangedbetween the radiation conversion element and the further radiationconversion element.

In accordance with at least one embodiment of the semiconductorcomponent, the radiation conversion element and the further radiationconversion element are arranged one above the other on the semiconductorchip.

In a configuration in which the further radiation conversion elementcomprises a further quantum structure, the radiation conversion elementcan comprise a further substrate. The radiation conversion element andthe further radiation conversion element can thus be producedindependently of one another during production and subsequently bearranged one on top of the other or alongside one another.Alternatively, the radiation conversion element and the furtherradiation conversion element can comprise a common substrate. By way ofexample, the quantum structure and the further quantum structure may beintegrated into a common semiconductor layer sequence or at leastsuccessively be deposited epitaxially on a common substrate.

In accordance with at least one embodiment of the semiconductorcomponent, the semiconductor component comprises a further semiconductorchip. By way of example, the further radiation conversion element isarranged on the further semiconductor chip. The radiation generated bythe further semiconductor chip can be identical to the primary radiationof the semiconductor chip. Alternatively, the peak wavelength of thefurther radiation can be different than the first peak wavelength of theprimary radiation.

In accordance with at least one embodiment of the semiconductorcomponent, the further radiation conversion element is formed by aphosphor embedded into an encapsulation of the semiconductor chip. Theencapsulation contains for example a polymer material that istransmissive to the primary radiation, for instance an epoxy or asilicone.

During the production of the semiconductor component, the encapsulationis formed for example by means of a molding compound that is molded ontothe semiconductor chip, which in particular has already beenelectrically contacted.

In accordance with at least one embodiment of the semiconductorcomponent, the emitter is the further semiconductor chip. By way ofexample, the further semiconductor chip has an active region forgenerating the third peak wavelength. By way of example, the activeregion of the further semiconductor chip containsAl_(x)In_(y)Ga_(1-x-y)P or Al_(x)In_(y)Ga_(1-x-y)As, in each case where0≦x≦1, 0≦y≦1 and x+y≦1.

In accordance with at least one embodiment of the semiconductorcomponent, the further semiconductor chip and the semiconductor chip areembedded into a reflector layer. A body that is radiation-transmissiveto the third peak wavelength is arranged on the further semiconductorchip. The reflector layer adjoins the radiation-transmissive body andthe radiation conversion element. The radiation-transmissive body andthe radiation conversion element are at least regionally free of thereflector layer on an emission side of the semiconductor component. In avertical direction, that is to say in a direction running perpendicularto a main extension plane of the active region of the semiconductorchip, the radiation conversion element and the radiation-transmissivebody end for example at the same height or substantially at the sameheight, for example with a deviation of at most 50 μm. The process offorming the reflector layer is simplified as a result.

In accordance with at least one embodiment of the semiconductorcomponent, a dielectric coating is arranged on the radiation conversionelement. The dielectric coating comprises for example a plurality ofdielectric layers, wherein layers adjoining one another in each casehave mutually different refractive indices. The dielectric coating hasfor example a wavelength-selective transmission. The transmission isthus greater for one spectral range than for another spectral range. Byway of example, the dielectric coating is designed to be reflective forat least one radiation portion, for example the primary radiation orpart of the primary radiation. Alternatively or supplementarily, theemitted spectrum can be prefiltered by means of the dielectric coating,for example with regard to specific customer requirements.

In accordance with at least one embodiment of the semiconductorcomponent, a scattering layer is arranged on the radiation conversionelement. By way of example, the scattering layer is arranged on the sideof the radiation conversion element facing away from the semiconductorchip. The scattering layer contains for example scattering particleshaving a concentration of between 10% by weight and 30% by weightinclusive, for example between 15% by weight and 25% by weightinclusive. A layer thickness of the scattering layer is for examplebetween 10 μm and 30 μm inclusive. The scattering particles contain forexample titanium dioxide, aluminum oxide or zirconium oxide.

In accordance with at least one embodiment of the semiconductorcomponent, the quantum structure is arranged on the side of thesubstrate facing the semiconductor chip. The heat loss arising in thequantum structure can thus be dissipated via the semiconductor chip. Ina departure from this, the quantum structure can also be arranged on theside of the substrate facing away from the semiconductor chip.

In accordance with at least one embodiment of the semiconductorcomponent, the radiation conversion element has a coupling-outstructure. The coupling-out structure is provided for increasing thecoupling-out of radiation from the radiation conversion element. By wayof example, the coupling-out structure is arranged on the side of thesubstrate facing the quantum structure. By way of example, thecoupling-out structure is formed by means of a structured growth area ofthe substrate. Furthermore, the coupling-out structure can be arrangedon the side of the quantum structure facing away from the substrate.Alternatively, the coupling-out structure can be arranged on the side ofthe substrate facing away from the quantum structure. By way of example,the coupling-out structure is embodied in the form of a roughening ofthe substrate.

In accordance with at least one embodiment of the semiconductorcomponent, the semiconductor component is embodied as asurface-mountable component (surface mounted device, SMD). Thesemiconductor component comprises, in particular on the mounting areafacing away from the emission side, at least two contacts for theexternal electrical contacting of the semiconductor component.

An illumination device in accordance with at least one embodimentcomprises at least one semiconductor component and a connection carrier,on which the semiconductor component is arranged. The connection carriercan be a printed circuit board, for example. The semiconductor componentcan have one or more of the features mentioned above.

In accordance with at least one embodiment of the illumination device,the illumination device is designed for the backlighting of a displaydevice, for a projection, for a flashlight or for a spotlight/headlight.

In particular the following effects can be achieved with the describedsemiconductor component and the illumination device.

A radiation conversion element having a quantum structure grownepitaxially, in particular, can be distinguished by a high thermalstability. By way of example, secondary radiation in the red spectralrange or in the green spectral range can have the high thermal stabilityof a light emitting diode based on nitride compound semiconductormaterial, in particular on Al_(x)In_(y)Ga_(1-x-y)N. Furthermore, in thecase of such a radiation conversion element, the emission wavelength issettable in a simple manner, in particular by the variation of the layerthicknesses and the materials of the quantum structure. The degree ofconversion is settable in a simple and reliable manner by means of thenumber of quantum layers. As an alternative to an epitaxial deposition,some other deposition method is also conceivable, for examplesputtering. Photoluminescent structures can thus be producedparticularly cost-effectively.

Furthermore, it has been found that the optical excitation of a quantumstructure that emits in the green spectral range, for example on thebasis of Al_(x)In_(y)Ga_(1-x-y)N, is more efficient than a directradiation generation in such a quantum structure by electricalexcitation.

Furthermore, compared with radiation conversion elements comprisingphosphors, a spectrally narrowband emission, for example having a fullwidth at half maximum (FWHM) of approximately 30 nm, may be achievedwhile phosphors typically bring about an emission with a full width athalf maximum of between approximately 50 and 100 nm. As a result, ahigher color purity can be achieved, as a result of which a high gamutis achievable with high efficiency.

Moreover, a spatial separation between the radiation conversion and thescattering of the radiation can be effected in the radiation conversionelement, for example by a radiation conversion in the quantum structureand a scattering by a coupling-out structure of the substrate, forinstance on the emission side.

Radiation conversion elements having a quantum structure can furthermorebe distinguished by a small layer thickness. While radiation conversionelements comprising phosphors typically have a layer thickness ofapproximately 100 μm, with a radiation conversion element having aquantum structure a layer thickness of less than 1 μm, for examplebetween 100 nm and 1 μm, may be achieved. The heat loss arising duringoperation can thus be dissipated more efficiently.

Furthermore, it is possible to shorten iteration cycles during theproduction of new semiconductor components in the development phase, inparticular by virtue of the flexible adaptability of the radiationconversion element.

The side of the substrate facing away from the quantum structure canfurthermore fulfill additional optical functions, for example thefunction of an in particular wavelength-selective mirror or filter,and/or the function of a coupling-out structure, for example of aroughening.

The semiconductor component furthermore comprises at least two radiationsources which emit in a narrowband fashion in particular in comparisonwith conversion elements based on phosphors, namely the semiconductorchip and the conversion element having the quantum structure. A highgamut can thus be achieved in a simplified manner. Furthermore, theemission spectrum of the semiconductor component is adaptable in asimple and reliable manner already just by the adaptation of theradiation conversion element, for instance of the layer sequence and/orof the layer thicknesses, to customer-specific requirements.

Furthermore, the emission characteristic can be modified in a simplemanner, for example for generating a spatially directed emission.

Scattering layers or structures of the semiconductor componentfurthermore bring about an efficient color mixing. By means of adielectric coating, for example, a wavelength-selective coupling-outand/or the formation of a resonant cavity for the generated radiationand/or a prefiltering of the spectrum of the semiconductor component canbe achieved in a simple and reliable manner.

Moreover, an efficient coupling into the radiation conversion elementand/or an efficient coupling-out from the semiconductor component can beachieved in a simple manner, for example by means of a structure whichis formed in the substrate and which brings about a refractive indexgradient.

BRIEF DESCRIPTION OF THE DRAWINGS

Further configurations and expediences will become apparent from thefollowing description of the exemplary embodiments in association withthe figures.

In the figures:

FIG. 1A shows one exemplary embodiment of a semiconductor component inschematic sectional view;

FIG. 1B shows one exemplary embodiment of a semiconductor chip;

FIGS. 1C to 1G show various exemplary embodiments of a radiationconversion element;

FIG. 2A shows one exemplary embodiment of a semiconductor component;

FIG. 2B shows one exemplary embodiment of a semiconductor chip;

FIGS. 3A, 3B, 4A, 4B, 5A, 5B, 6, 7A, 7B, 8A, 8B, 8C and 8D in each caseshow an exemplary embodiment of a semiconductor component;

FIG. 9 shows one exemplary embodiment of an illumination device; and

FIGS. 10A, 10B, 11A, 11B and 12 in each case show an exemplaryembodiment of a semiconductor component.

Elements that are identical, of identical type or act identically areprovided with identical reference signs in the figures.

The figures are in each case schematic illustrations and therefore notnecessarily true to scale. Rather, comparatively small elements and inparticular layer thicknesses may be illustrated with exaggerated sizefor the purpose of elucidation.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1A shows one exemplary embodiment of a semiconductor component inschematic sectional view. The semiconductor component 1 comprises asemiconductor chip 2 provided for generating a primary radiation havinga first peak wavelength. The first peak wavelength of the primaryradiation is in the blue spectral range. A radiation conversion element3 is arranged on the semiconductor chip 2 and converts primary radiationgenerated in the semiconductor chip 2 during the operation of thesemiconductor component partly into secondary radiation having a secondpeak wavelength. The semiconductor component 1 thus emits mixedradiation comprising the primary radiation and the secondary radiation.

The semiconductor component 1 furthermore comprises a first contact 61and a second contact 62. The first contact 61 and the second contact 62are partial regions of a leadframe. The leadframe is embedded in placesin a housing body 6. The semiconductor chip 2 is arranged in a cavity 67of the housing body 6.

A radiation conversion element 3 having a quantum structure is arrangedon the semiconductor chip 2. Various configurations of the radiationconversion element are described with reference to FIGS. 1C to 1G.

Furthermore, two or more, for example three, radiation conversionelements 3 of identical type can also be arranged one above another. Inthis context, of identical type means that the peak wavelengths of theradiation conversion elements do not differ, or differ only slightlyfrom one another, for example by at most 20 nm. The degree of conversionis thus settable in a simple manner by means of the number of radiationconversion elements.

The radiation conversion element 3 is fixed to the semiconductor chip bymeans of a fixing layer 8. The fixing layer 8 is expediently formed bymeans of a material that is transmissive to the primary radiation. Byway of example, the fixing layer 8 contains a polymer material, forinstance a silicone. Preferably, the refractive index is between 1.5 andthe refractive index of the material of the semiconductor chip adjoiningthe fixing layer. The greater the refractive index of the fixing layer8, the smaller the proportion of radiation that is reflected at theinterface between the semiconductor chip 2 and the fixing layer 8. Sucha fixing layer is likewise suitable for the subsequent exemplaryembodiments, even if the fixing layer is not shown in all of thefigures, for the sake of simplified illustration.

The semiconductor chip 2 and the radiation conversion element 3 aresurrounded by a reflector layer 7. The reflector layer in particulardirectly adjoins the semiconductor chip 2 and the radiation conversionelement 3.

The reflector layer 7 is formed for example by means of a polymermaterial admixed with reflective particles. By way of example, thereflector layer contains a silicone or an epoxy. The particles containfor example titanium oxide, zirconium oxide or aluminum oxide.

The reflector layer 7 is used to avoid a situation where radiation canemerge laterally from the semiconductor chip 2 or the radiationconversion element 3. Therefore, the generated radiation does notimpinge on the housing body 6. The material for the housing body cantherefore be selected largely independently of its optical properties,for example with regard to a high mechanical stability or a high thermalstability. The fixing of the semiconductor component 1, for example bymeans of soldering, is thus simplified.

In a vertical direction the semiconductor component 1 extends between anemission side 12 and a mounting side 13 of the semiconductor component,said mounting side being situated opposite the emission side 12.

At the emission side 12 of the semiconductor component 1, the radiationconversion element 3 is free of material of the reflector layer 7 atleast in places, preferably completely or substantially completely, forexample to the extent of at least 90% of the area of the radiationconversion element.

The first contact 61 and the second contact 62 are formed at themounting side 13 of the semiconductor component and are electricallyconductively connected to the semiconductor chip 2. The semiconductorcomponent is embodied as a surface-mountable semiconductor component.

One configuration of the semiconductor chip 2 is shown schematically inFIG. 1B. The semiconductor chip 2 has a first connection area 25 and asecond connection area 26 on the rear side facing the mounting side 13.The semiconductor chip 2 comprises a semiconductor body having asemiconductor layer sequence 200 having an active region 20 provided forthe radiation generation of the primary radiation. The active region 20is situated between a first semiconductor layer 21 and a secondsemiconductor layer 22, wherein the first semiconductor layer and thesecond semiconductor layer differ from one another with regard to theconduction type at least in places, such that the active region 20 issituated in a pn junction. The in particular epitaxially depositedsemiconductor layers of the semiconductor chip 2 are arranged on acarrier 29. In the exemplary embodiment shown, the carrier is a growthsubstrate for the semiconductor layers of the semiconductor chip. By wayof example, the carrier contains sapphire or silicon carbide.

In the exemplary embodiment illustrated in FIG. 1A, the semiconductorchip 2 is mounted in a so-called flip-chip arrangement, such that thefirst connection area 25 and the second connection area 26 are arrangedon the side of the semiconductor component facing the mounting side 13.In a plan view of the semiconductor component, the first contact 61 andthe first connection area 25, and also the second contact 62 and thesecond connection area 26 respectively overlap.

During the production of the semiconductor component 1, the leadframehaving the first contact 61 and the second contact 62 can be present ina leadframe assemblage for a multiplicity of semiconductor components.The semiconductor chip 2 is mounted on the leadframe assemblage. Beforeor after the mounting of the semiconductor chips, a material for thehousing body 6 is molded around the leadframe assemblage. The radiationconversion element 3 is applied on the semiconductor chip 2. This can becarried out before or after the semiconductor chips 2 are fixed to theleadframe assemblage. A molding compound for the reflector layer ismolded around the semiconductor chips fixed to the leadframe assemblage.The individual semiconductor components 1 arise as a result of asingulation step in which both the leadframe assemblage and the materialfor the housing bodies are severed. The housing bodies 6 thus arise onlyupon the singulation of the semiconductor components 1. The sidesurfaces of the housing body 6 which delimit the semiconductor component1 in a lateral direction can therefore have singulation traces, forexample sawing traces or traces of a laser separation method, at leastin places. Such semiconductor components 1 can be produced particularlycost-effectively and compactly.

Exemplary embodiments of the radiation conversion element 3 are shown inan enlarged illustration in FIGS. 1C to 1G. The radiation conversionelement 3 comprises a quantum structure 30. The quantum structurecomprises quantum layers 31 between which barrier layers 32 arearranged.

The quantum layers 31 and the barrier layers 32 form a multi quantumwell structure. In such quantum structures, a quantization takes placewithin the quantum layers along exactly one spatial direction. Suchquantum structures are producible particularly reliably and aredistinguished by a high efficiency. However, other quantum structuresfrom among those mentioned in the introduction can also be employed.

The number of quantum layers 31 can be varied within wide limits. By wayof example, the quantum structure 30 comprises between two and a hundredquantum layers inclusive, for example fifty quantum layers.

A layer thickness of the quantum layers is preferably between 1 nm and10 nm inclusive. A layer thickness of the barrier layers 32 ispreferably between 3 nm and 100 nm inclusive, for example 15 nm. Thebarrier layers are preferably embodied in a nominally undoped fashion.In a departure therefrom, however, the barrier layers can also be doped.

For generating green secondary radiation, the quantum layers 31preferably comprise Al_(x)In_(y)Ga_(1-x-y)N. By increasing theproportion of indium and/or widening the quantum layers 31, the peakwavelength of the secondary radiation may be increased.

By further increasing the proportion of indium, secondary radiationhaving a peak wavelength in the yellow or red spectral range may also beachieved. Furthermore, the material system Al_(x)In_(y)Ga_(1-x-y)P isalso suitable for secondary radiation in the red spectral range.

For peak wavelengths of greater than or equal to 100 nm, the quantumlayers are preferably free of aluminum or substantially free ofaluminum, for example where x≦0.05. Furthermore, the indium content y ispreferably approximately 50%, for example between 0.45 and 0.55inclusive, in particular between 0.44 and 0.52 inclusive. Such materialscan be deposited epitaxially with high crystal quality on galliumarsenide.

The radiation conversion element 3 furthermore comprises a substrate 35.The substrate 35 can be the growth substrate for the epitaxialdeposition of the quantum structure 30. Particularly in the case of agrowth substrate that is not radiation-transmissive to the primaryradiation, for example in the case of gallium arsenide, the quantumstructure 30 can also be transferred to a substrate different than thegrowth substrate, for example to a glass substrate. In this case,therefore, the substrate is different than a growth substrate for thequantum structure 30 and mechanically stabilizes the quantum structure.The growth substrate is no longer required for this purpose and can beremoved, such that the radiation conversion element is free of a growthsubstrate.

A main extension plane of the substrate 35 runs parallel to a mainextension plane of the semiconductor chip, in particular parallel to amain extension plane of the active region of the semiconductor chip. Thesubstrate 35 covers the semiconductor chip 2 over the whole area in theexemplary embodiment shown. In a departure therefrom, a smaller coveragecan be expedient. Preferably, the substrate covers the semiconductorchip over a large area, in particular to the extent of at least 20% orto the extent of at least 50%.

The quantum structure 30 can be arranged on the side of the substrate 35facing away from the semiconductor chip 2 (FIG. 1C) or on the side ofthe substrate 35 facing the semiconductor chip 2 (FIG. 1D).

In the exemplary embodiment illustrated in FIG. 1E, a dielectric coating5 is formed on the radiation conversion element 3, in particular on theside of the substrate 35 facing away from the quantum structure 30. Thedielectric coating can be embodied in a multilayered fashion comprisinga plurality of layers, wherein adjacent layers of the dielectric coatingdiffer from one another with regard to the refractive index. Thedielectric coating 5 can be embodied for example such that the primaryradiation is at least partly reflected back into the radiationconversion element 3 and the secondary radiation emerges virtuallywithout being impeded. Furthermore, a resonant cavity for at least oneradiation portion, that is to say for the primary radiation and/or thesecondary radiation, can be formed by means of the dielectric coating 5.

As an alternative to, or to supplement, a dielectric coating 5, it ispossible, as illustrated in FIG. 1F, to arrange a scattering layer 55 onthe radiation conversion element 3. By way of example, the scatteringlayer 55 contains a polymer material in which scattering particles arearranged. By way of example, a layer having a thickness of between 10 μmand 30 μm inclusive and having a proportion of scattering particles inpercent by weight of between 10% and 30% inclusive, preferably between15% and 25% inclusive, is suitable. The homogeneity of the emittedradiation with regard to the angle dependence of the color locus can beimproved by means of the scattering layer. Furthermore, the scatteringin the scattering layer 55 takes place spatially at a distance from theradiation conversion in the quantum structure 30. Radiation conversionand scattering are thus settable largely independently of one another.Furthermore, the radiation conversion element 3, in particular thesubstrate 35, can comprise a coupling-out structure 58, as is shown inFIG. 1G. In the exemplary embodiment shown, the coupling-out structureis formed on the side of the substrate 35 facing away from the quantumstructure 30. The coupling-out structure can be formed for example in anirregular fashion, for instance by means of a roughening.

Alternatively or additionally, the substrate 35 can also have acoupling-out structure on the side facing the quantum structure 30. Byway of example, the substrate 35 can be a prestructured substrate, forinstance a prestructured sapphire substrate.

In addition to such a coupling-out structure, the radiation conversionelement, as described in FIGS. 1E to 1F, can comprise a scattering layer55 and/or a dielectric coating 5.

The described configurations of the radiation conversion element 3 arealso applicable to the exemplary embodiments of a semiconductorcomponent 1 described below. For the sake of simplified illustration,details of the radiation conversion element 3 are not shown in thefurther figures.

The exemplary embodiment illustrated in FIG. 2A substantiallycorresponds to the exemplary embodiment described in association withFIG. 1A. In contrast thereto, the semiconductor chip 2 is embodied as asemiconductor chip in which a connection area is arranged on the frontside and a connection area is arranged on the rear side of thesemiconductor chip. The side of the semiconductor chip facing theemission side is regarded as the front side.

FIG. 2B shows one exemplary embodiment of such a semiconductor chip 2.In a departure from the semiconductor chip described in FIG. 1B, thecarrier 29 is different than a growth substrate for the semiconductorlayers. Such a semiconductor chip is also referred to as a thin-filmsemiconductor chip. The carrier 29 serves for mechanically stabilizingthe semiconductor layers, such that the growth substrate is no longerrequired for this purpose and can be removed during production. Forelectrically contacting the first semiconductor layer 21, thesemiconductor chip 2 has a plurality of recesses 23 extending throughthe second semiconductor layer and the active region 20. A firstconnection layer 250 is arranged in the recesses 23 and is electricallyconductively connected to the first semiconductor layer 21. Thesemiconductor body having the semiconductor layer sequence 200 is fixedto the carrier 29 by means of a connecting layer 28, for example anelectrically conductive solder layer or adhesive layer. The electricalcontacting of the first semiconductor layer is effected via the firstconnection layer 250, the connecting layer 28 and the carrier 29 via thefirst connection area 25. The electrical contacting of the secondsemiconductor layer is effected via a second connection layer 260 and afront-side second connection area 26. The second connection area 26 isarranged laterally with respect to the semiconductor body 200, with theresult that a shading of the active region 20 byradiation-nontransmissive layers for contacting, for example metallayers, is avoided. The second connection area 26 is electricallyconductively connected to the second contact 62 via a connecting line69, for example a wire bond connection. The second connection layer 260is embodied in particular as a mirror layer for the radiation generatedin the active region. In the case of such a semiconductor chip 2, thelateral coupling-out of radiation is reduced in favor of an increasedfront-side coupling-out of radiation. Even in the absence of a reflectorlayer laterally adjoining the semiconductor chip, the primary radiationemerges predominantly at the side facing the radiation conversionelement.

In the exemplary embodiments described below, both a semiconductor chipas described in association with FIG. 1B and a semiconductor chip asdescribed in association with FIG. 2B can be employed.

The exemplary embodiment illustrated in FIG. 3A substantiallycorresponds to the exemplary embodiment described in association withFIG. 1A.

In contrast thereto, the semiconductor chip 2 is embedded into anencapsulation 65. The encapsulation 65 is embodied such that it isradiation-transmissive to the primary radiation and the secondaryradiation, and so it can also be arranged in the beam path between thesemiconductor chip 2 and the emission side 12.

In this exemplary embodiment, the housing body 6, in particular theinner surface of the cavity 67, can also be embodied in a reflectivefashion.

The semiconductor component 1 furthermore comprises an emitter 4 inaddition to the semiconductor chip 2 and the radiation conversionelement 3. In this exemplary embodiment, the emitter 4 is embodied as afurther radiation conversion element 41. By way of example, theradiation conversion element 3 is provided for generating secondaryradiation in the green spectral range and the further radiationconversion element 41 is provided for generating radiation in the redspectral range. Together with the primary radiation of the semiconductorchip 2 the semiconductor component 1 thus emits radiation having arespective peak wavelength in the red, green and blue spectral ranges.

In the exemplary embodiment shown, the radiation conversion element 3and the further radiation conversion element 41 are arranged alongsideone another on the semiconductor chip 2. The radiation conversionelement 3 and the further radiation conversion element 41 can inparticular also adjoin one another.

The further radiation conversion element 41 comprises a phosphor forgenerating a radiation having a third peak wavelength. The phosphor canbe embedded for example into a matrix material, for example a siliconeor an epoxy. Alternatively, the further radiation conversion element canbe embodied as a ceramic comprising the phosphor. Phosphors forgenerating secondary radiation, for example in the red spectral range,are known per se and are not described in greater detail in the presentcase.

In addition to the semiconductor chip 2 with narrowband emission and theradiation conversion element 3 with narrowband emission, thesemiconductor component 1 comprises an emitter with comparativelybroadband emission, for example having a full width at half maximum of50 nm to 100 nm.

The exemplary embodiment illustrated in FIG. 3B substantiallycorresponds to the exemplary embodiment described in association withFIG. 3A. In contrast thereto, the housing body 6 is formed by areflector layer 7 adjoining the semiconductor chip 2, the radiationconversion element 3 and the emitter 4. During the production of thesemiconductor component, the housing body is formed by means of amolding compound only after the semiconductor chip 2 with the radiationconversion element 3 and the emitter 4 has already been fixed to thefirst contact 61 and the second contact 62. Such a semiconductorcomponent 1 can have a particularly small component height, wherein thehousing body 6 at the emission side 12 does not extend or at least doesnot significantly extend beyond the radiation conversion element 3. Itgoes without saying that such a housing form is also suitable for asemiconductor component 1 which, as described in association with FIG.1A, does not comprise an emitter 4 in addition to the semiconductor chip2 and the radiation conversion element 3.

The exemplary embodiments illustrated in FIGS. 4A and 4B substantiallycorrespond to the exemplary embodiments described in association withFIGS. 3A and 3B, respectively. In contrast thereto, the emitter 4 isformed in each case by a further radiation conversion element comprisinga further quantum structure 42 arranged on a further substrate 43. Thefurther quantum structure 42 and the further substrate 43 can beembodied as described in association with FIGS. 1C to 1G with regard tothe radiation conversion element 3. Such a semiconductor component thusemits three radiation portions having mutually different peakwavelengths, which are in each case particularly narrowband, for examplehaving a full width at half maximum of between 25 nm and 40 nm.

The exemplary embodiments shown in FIGS. 5A and 5B substantiallycorrespond to the exemplary embodiments described in association withFIGS. 3B and 4B, respectively.

In contrast thereto, the emitter 4, that is to say the further radiationconversion element 41 containing phosphor in FIG. 5A and the furtherquantum structure 42 with the further substrate 43 in FIG. 5B, isoptically isolated from the radiation conversion element 3 by means ofthe reflector layer 7. An optical crosstalk and an associated undesiredradiation absorption or excitation of the adjacent radiation conversionelement by a radiation transfer between the radiation conversion element3 and the emitter 4 can thus be avoided. In a plan view of thesemiconductor component 1, the reflector layer 7 regionally covers thefront side of the semiconductor chip 2 facing the emission side 12.

The exemplary embodiment illustrated in FIG. 6 substantially correspondsto the exemplary embodiment described in association with FIG. 3A. Incontrast thereto, the emitter 4 is formed by means of a phosphorembedded into the encapsulation 65. The emitter 4 is thus embodied as avolume converter that emits radiation in particular in the red spectralrange. On the emission side 12, the radiation conversion element 3 isfree of the encapsulation 65. An undesired absorption of the secondaryradiation generated in the radiation conversion element 3 in the emitter4 is thus reduced. The emitter 4 in the form of the encapsulation withthe phosphor adjoins both the semiconductor chip 2 and the radiationconversion element 3.

Furthermore, the semiconductor chip 2 is embodied as a semiconductorchip having two front-side connection areas. The electrical contactingof the semiconductor chip 2 is effected in each case via connectinglines 69. It goes without saying that, in a departure therefrom, asemiconductor chip embodied as described in association with FIG. 1B or2B can also be employed. Furthermore, the semiconductor chip illustratedin FIG. 6 is also suitable for the further exemplary embodiments.

The exemplary embodiments illustrated in FIGS. 7A and 7B substantiallycorrespond to the exemplary embodiment described in association withFigure A. In contrast thereto, the semiconductor component 1 is free ofa leadframe. The first contact 61 and the second contact 62 are formeddirectly on the semiconductor chip 2. The housing body 6 is formed by areflector layer 7 molded onto the semiconductor chip 2, the radiationconversion element 3 and the emitter 4. In order to produce such asemiconductor component, the semiconductor chips can be applied on anauxiliary carrier, for example a foil, and a material for the reflectorlayer 7 can subsequently be molded around them. In particular a moldingmethod, for example foil assisted molding, is suitable for this purpose.

As already described above, a silicone or an epoxy embodied in areflective fashion is suitable, for example, as material for thereflector layer 7.

In this semiconductor component 1, too, the side surfaces of thesemiconductor component 1 arise only upon singulation into individualsemiconductor components.

Such semiconductor components are producible particularly compactly and,in terms of their lateral extents, are only slightly larger than thesemiconductor chips. Such housing forms are therefore also referred toas CSP (chip size package).

In FIG. 7A, the emitter 4 is formed by a further radiation conversionelement containing phosphor. In FIG. 7B, the further radiationconversion element comprises a further quantum structure 42.

The exemplary embodiments described in FIGS. 8A to 8D differ from theprevious exemplary embodiments in that the radiation conversion element3 and the emitter 4, in particular in the form of a further radiationconversion element, are arranged in the vertical direction above thesemiconductor chip 2. Both the radiation conversion element 3 and theemitter 4 can thus cover the semiconductor chip 2 over the whole area orsubstantially over the whole area.

For the rest, the exemplary embodiment illustrated in FIG. 8Acorresponds to the exemplary embodiment described in association withFIG. 3A. For the rest, the exemplary embodiment illustrated in FIG. 8Bcorresponds to the exemplary embodiment described in association withFIG. 4B. In particular, the emitter 4 comprises a further quantumstructure 42. In the exemplary embodiment shown, the further quantumstructure 42 is arranged on a further substrate 43. The further quantumstructure 42 and the quantum structure 30 of the radiation conversionelement 3 can thus be produced independently of one another and then bearranged one on top of the other. In a departure therefrom, the furtherquantum structure 42 and the quantum structure 30 can also beepitaxially deposited in a common semiconductor layer sequence on acommon substrate. In this case, therefore, the quantum structure 30 andthe further quantum structure 42 are monolithically integrated into acommon semiconductor layer sequence and produced in particular in acommon epitaxial production method.

For the rest, the exemplary embodiment illustrated in FIG. 8Ccorresponds to the exemplary embodiment described in association withFIG. 3B.

The exemplary embodiment illustrated in FIG. 8D corresponds to theexemplary embodiment described in association with FIG. 2A, apart fromthe emitter 4 arranged on the radiation conversion element 3.

In the exemplary embodiments illustrated in FIGS. 8C and 8D, too, theemitter 4 can comprise a phosphor or a further quantum structure.

FIG. 9 shows one exemplary embodiment of an illumination device 11. Theillumination device 11 comprises a plurality of semiconductor components1 arranged on a connection carrier 15, for example a printed circuitboard. The semiconductor components 1 are embodied merely by way ofexample as described in association with FIG. 7A. The other exemplaryembodiments of the semiconductor component 1 can also be used. In theexemplary embodiment shown, the illumination device 11 is designed forcoupling radiation into an optical waveguide 19. By way of example, theillumination device 11 serves for the backlighting of a display device,for instance an LCD.

In a departure therefrom, the illumination device 11 can also bedesigned for a spotlight/headlight or a flashlight or for a projection.

With the exemplary embodiments of the semiconductor components 1described in the present application, a high gamut with at the same timehigh efficiency is achievable. The semiconductor components 1 aretherefore particularly suitable for such an illumination device 11.

The exemplary embodiment illustrated in FIG. 10A substantiallycorresponds to the exemplary embodiment described in association withFIG. 3A. In contrast thereto, the emitter 4 is embodied as a furthersemiconductor chip 44. The further semiconductor chip has an activeregion 440 provided for generating the radiation having the third peakwavelength. In the present exemplary embodiment, the furthersemiconductor chip emits radiation in the red spectral range. By way ofexample, the active region of the further semiconductor chip 44 containsAl_(x)In_(y)Ga_(1-x-y)P or Al_(x)In_(y)Ga_(1-x-y)As.

The semiconductor component 1 furthermore comprises a third contact 63in addition to the first contact 61 and the second contact 62. The firstcontact 61 serves as a common contact for the semiconductor chip 2 andthe further semiconductor chip 44. During the operation of thesemiconductor component 1, the semiconductor chip 2 and the furthersemiconductor chip 44 are operable independently of one another.

The exemplary embodiment illustrated in FIG. 10B substantiallycorresponds to the exemplary embodiment described in association withFIG. 5B. In contrast thereto, the semiconductor component 1, asdescribed in association with FIG. 10A, comprises an emitter 4 in theform of a further semiconductor chip 44. A radiation-transmissive body48 is arranged on the further semiconductor chip 44. By way of example,the radiation-transmissive body contains a glass. The reflector layer 7adjoins the further semiconductor chip 44, the radiation-transmissivebody 48, the semiconductor chip 2 and the radiation conversion element3. In particular, the further semiconductor chip 44 and theradiation-transmissive body 48 are optically isolated from thesemiconductor chip 2 and the radiation conversion element 3 by thereflector layer 7. By means of the radiation-transmissive body 48, thereflector layer 7 can be embodied in a simplified manner such that thefurther semiconductor chip 44 is not covered by the reflector layer 7.In particular, the radiation-transmissive body 48 and the radiationconversion element 3 at the emission side 12 end at the same height orsubstantially at the same height.

In other words, the top sides—facing the emission side 12—of theradiation-transmissive body 48 and of the radiation conversion element 3run in one plane.

The exemplary embodiment described in FIG. 11A substantially correspondsto the exemplary embodiment described in association with FIG. 5A. Incontrast thereto, the emitter 4 embodied as a further radiationconversion element 41 is not arranged on the semiconductor chip 2, butrather on a further semiconductor chip 44. The further semiconductorchip 44 can emit radiation in particular with the same peak wavelengthas the semiconductor chip 2. During the operation of the semiconductorcomponent, the ratio of the radiation emitted by the emitter 4 and theradiation emitted by the radiation conversion element 3, in contrast tothe exemplary embodiment illustrated in FIG. 5A, is settable bydifferent driving of the semiconductor chip 2 and of the furthersemiconductor chip 44. The further semiconductor chip 44 and the emitter4 are optically decoupled from the semiconductor chip 2 and theradiation conversion element 3 by the reflector layer 7.

As an alternative to the exemplary embodiment illustrated in FIG. 11A,the emitter 4 can also be formed by means of a further quantum layer 42on a further substrate 43, as illustrated in FIG. 11B.

The exemplary embodiment illustrated in FIG. 12 substantiallycorresponds to the exemplary embodiment described in association withFIG. 10A. In contrast thereto, the radiation conversion element 3 in aplan view of the semiconductor component 1 extends both over thesemiconductor chip 2 and over the further semiconductor chip 44. Aradiation-transmissive body 48 on the further semiconductor chip 44 istherefore not necessary. Expediently, the peak wavelength of the furthersemiconductor chip 44 is of a magnitude such that the emitted radiationis not or at least not significantly absorbed upon passing through theradiation conversion element 3.

By way of example, the radiation conversion element 3 is provided forabsorbing radiation in the blue spectral range and for emittingradiation in the green spectral range. Radiation in the red spectralrange emitted by the further semiconductor chip 44 is therefore notabsorbed by the radiation conversion element 3.

Furthermore, in contrast to FIG. 10A, the further semiconductor chip 44is embodied as a flip-chip, such that a front-side contacting of thesemiconductor chip is not necessary. The large-area arrangement of theradiation conversion element on the semiconductor chip 2 and the furthersemiconductor chip 44 is thus simplified.

The invention is not restricted by the description on the basis of theexemplary embodiments. Rather, the invention encompasses any novelfeature and also any combination of features, which in particularincludes any combination of features in the patent claims, even if thisfeature or this combination itself is not explicitly specified in thepatent claims and in the exemplary embodiments.

1-17. (canceled)
 18. A semiconductor component comprising: a firstsemiconductor chip configured to generate a primary radiation having afirst peak wavelength; and a first radiation conversion element arrangedon the first semiconductor chip, the first radiation conversion elementcomprising: a quantum structure that converts the primary radiation atleast partly into secondary radiation having a second peak wavelength;and a substrate transmissive to the primary radiation.
 19. Thesemiconductor component according to claim 18, wherein the firstradiation conversion element contains Al_(x)In_(y)Ga_(1-x-y)N,Al_(x)In_(y)Ga_(1-x-y)P or Al_(x)In_(y)Ga_(1-x-y)As.
 20. Thesemiconductor component according to claim 18, wherein the first peakwavelength is less than the second peak wavelength.
 21. Thesemiconductor component according to claim 18, wherein the semiconductorcomponent comprises an emitter configured to emit radiation having athird peak wavelength.
 22. The semiconductor component according toclaim 21, wherein a reflector layer is arranged in a beam path betweenthe emitter and the first radiation conversion element.
 23. Thesemiconductor component according to claim 21, wherein the emitter is asecond radiation conversion element.
 24. The semiconductor componentaccording to claim 23, wherein the first radiation conversion elementand the second radiation conversion element are arranged alongside oneanother or one above the other on the first semiconductor chip.
 25. Thesemiconductor component according to claim 23, wherein the semiconductorcomponent comprises a second semiconductor chip, and wherein the secondradiation conversion element is arranged on the second semiconductorchip.
 26. The semiconductor component according to claim 23, wherein thesecond radiation conversion element comprises a phosphor embedded intoan encapsulation of the first semiconductor chip.
 27. The semiconductorcomponent according to claim 21, wherein the emitter is a secondsemiconductor chip, and wherein the second semiconductor chip has anactive region for generating the third peak wavelength.
 28. Thesemiconductor component according to claim 27, wherein the firstsemiconductor chip and the second semiconductor chip are embedded into areflector layer, wherein a body that is radiation-transmissive to thethird peak wavelength is arranged on the second semiconductor chip,wherein the reflector layer adjoins the radiation-transmissive body andthe first radiation conversion element, and wherein theradiation-transmissive body and the first radiation conversion elementare at least regionally free of the reflector layer on an emission sideof the semiconductor component.
 29. The semiconductor componentaccording to claim 18, wherein a dielectric coating is arranged on thefirst radiation conversion element, and wherein the dielectric coatinghas a wavelength-selective transmission.
 30. The semiconductor componentaccording to claim 18, wherein a scattering layer is arranged on thefirst radiation conversion element.
 31. The semiconductor componentaccording to claim 18, wherein the quantum structure is arranged on aside of the substrate facing the first semiconductor chip.
 32. Thesemiconductor component according to claim 18, wherein the firstradiation conversion element has a coupling-out structure.
 33. Anillumination device comprising: a connection carrier; and at least onesemiconductor component according to claim 18, wherein the at least onesemiconductor component is arranged the connection carrier.
 34. Theillumination device according to claim 33, wherein the illuminationdevice is designed for backlighting of a display device, for aprojection, for a flashlight or for a spotlight/headlight.
 35. Asemiconductor component comprising: a semiconductor chip configured togenerate a primary radiation having a first peak wavelength; a firstradiation conversion element arranged on the semiconductor chip, whereinthe first radiation conversion element comprises a first quantumstructure that converts the primary radiation at least partly intosecondary radiation having a second peak wavelength, wherein the firstradiation conversion element comprises a first substrate that istransmissive to the primary radiation; and an emitter for emittingradiation having a third peak wavelength, the emitter being a secondradiation conversion element, wherein the first and second radiationconversion elements are arranged one above the other on thesemiconductor chip, and wherein the second radiation conversion elementcomprises a phosphor or a second quantum structure arranged on a secondsubstrate.
 36. The semiconductor component according to claim 35,wherein the semiconductor component comprises a reflector layer, thereflector layer directly adjoining the semiconductor chip and the firstradiation conversion element.
 37. The semiconductor component accordingto claim 36, wherein the reflector layer adjoins the second radiationconversion element.